The present invention relates to a pressure exchanger for transmitting pressure energy from a first fluid flow to a second fluid flow.
Such a pressure exchanger is known, for example, from EP 0 298 097 B1 and serves for transmitting pressure energy from a first fluid flow to a second fluid flow. Such pressure exchangers are, in particular, applied in seawater desalination plants. In such plants, salt water is led under pressure at the entry side. The supplied seawater then flows over membranes, through which the desalinated water passes, and is led away as a second fluid flow. Highly concentrated brine arises at the entry side of the membrane, and this exits the plant under pressure. It is the task of the pressure exchanger to recover a part of the pressure energy which this exiting brine contains, and to lead it again to the supplied sea water, in order to reduce the energy requirement of the plant.
The problem with such prior art pressure exchangers of the construction type which is known from EP 0 298 097 B1, is the fact that any undesirable mixing of salt water and brine may occur in the pressure exchanger, since both fluid flows are not completely separated from one another.